John e



(No Model.) J, ELSWEET.

VALVE GEAR.

DI-0.275.871, Patented Apr. 17,1883.

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NETED STATES PATENT JOHN E. SWEET, OF SYRACUSE, NEW YORK.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 275,871, dated April 17, 1883,

Application filed December 16, 1881. Renewed November 6, 1882. (No model.)

To all whom it may concern Be it known that I, JOHN E. SWEET, residing at Syracuse, county of Onondaga, and State of New York, have invented certain new and useful Improvements in Valve-Gear for Engines, of which the following is a specitication.

The object of this invention is the use of a shifting eccentric on the main shaft of an engine by the governor without disturbing the lead of the slide-valve; and the invention consists in the combination of the shifting eccentrio with the ordinary slide-valve of an engine in such a manner that the eccentric may be shifted by the governor when the crank is at either dead-center without giving perceptible motion to the rocker-arm which operates the valve, as will hereinafter appear.

In the old devices for operating the slidevalves of engines it has not been possible, so far as I know, to maintainaconstant lead and cut-off ateach end of the stroke when the eccentric is changed from one position to another to vary the cut-off; but by my arrange ment of the relative positions of the operating devices this object is perfectly efft'ected, as will be readily understood by referring to Figure l in the accompanying drawings, in which the shifting eccentric is shown at A surrounding the shaft B, and is pivoted to the fly-wheel at O in such a position as to be free to move across the shaft and be operated by the governor at I), connected to the opposite side at E by the link F, or by any other operating device.

At G is the eccentric-rod leading to the rocker-arm H, the other end of which arm is attached to the valve-rod of the engine at K. Now, my new arrangement of the devices consists in so placing the rocker-arm or extending the length of the eccentric-rod that a line drawn through the center of the eccentric and another line drawn through the center of the pivot to which the eccentric-rod is attached, and the center of the rock-shaft, will always maintain an acute angle, as plainly shown by the diagram at Fig. 2 of the drawings, in which the shaft of the engine is shown at a, the dead-centers, say, at b and I), or with the piston at the ends of its stroke.

At 0 is shown the position of the eccentricrod. when the crank is at b, and 0 shows its position when the crank is atthe opposite end at b. The circle at at shows the path of the eccentric when at its greatest throw, and the circle at c the path of the eccentric at its least throw. The center of the eccentric in changing from its greatest to its least throw will move fromftof' when the crank is at 1). Consequently from this it will be seen that the eccentric may be shifted when the crank is at either dead-center without giving perceptible motion to the rocker-arm, and consequently to the valve, and therefore a shifting eccentric can be used without disturbing the lead of the valve.

It will be seen that the line c, drawn from the rocker-arm to the eccentric, when in midposition, is parallel to the dotted line 0 drawn from the end of the rocker-arm to the center of the eccentric, when it is diametrically opposite to its first position.

It is evident that such a connection is applicable to all kinds of engines in which slidevalves are worked, and where it is desirable to have them operate equally well at the opposite ends of the stroke, and it is also applicable to anykind of slide or reciprocating valves.

I therefore claim- 1. In a reciprocating engine, the combination of a shifting eccentric with an ordinary slide-valve, having an eccentric-rod and rocker-arm, arranged relatively to each other in such a manner that the eccentric may be shifted when the crank is at two diametricallyoppositepoints withoutanyperceptiblc change of motion being imparted to the valve, as hereinbefore setforth. V

2. The combination of the shifting eccentric, eccentric-rod, and rocker-arm with a governor for operating the slide-valve of an engine, as hereinbefore'set forth.

In witness whereof I have hereunto subscribed my name and affixed my seal in the presence of two subscribing witnesses.

' JOHN E. SWEE'IX. [L. s]

Witnesses:

EUGENE N. ELIOT, JOHN W. WENTWORTH. 

